The present invention relates to a device used for rotating disk shaped data carriers inside of disk player and/or recorders.
A disk player and/or recorder is used to read and/or write on disk shaped data carriers. Different types of disk shaped data carriers are known, e.g. magnetical and optical disk shaped data carriers. Data may be stored along tracks which form for example concentrical circles or a spiral on the disk shaped data carrier. The disk shaped data carriers typically have an opening at a center, which ideally has substantially a common center with the disk shaped data carrier and the concentrical circles or the spiral. The disk shaped data carrier is rotated by driving means which are linked directly or indirectly to its opening, i.e. the driving means"" rotation axis is made to correspond with the center of the disk. The data is read using reading means which follow the track. A servo system determines if the reading means deviate from the track being followed and if necessary move the reading means to reposition them on the track. The better the driving means"" rotation axis corresponds to the center of the disk, the better the concentrical circles or spiral rotate around their own center and the less the servo system has to correct deviations to compensate for an eccentricity of the concentrical circle""s or the spiral""s rotation.
A data reading and/or writing rate of a disk player and/or recorder depends for a part on a disk""s rotation speed. The reading and/or writing rate may for example be increased with a higher rotation speed of the disk. Typically a new problem arises in the disk player and/or recorder at higher rotation speeds. The player and/or recorder starts to vibrate, become more noisier and eventually to generate a greater number of reading and/or writing errors because the servo system may not anymore keep the reading means on track.
One reason for the new problem lies in the mass distribution of the disk shaped data carrier and parts fixed to it during its rotation. More precisely a mass center of the disk shaped data carrier and parts fixed to it may be located aside of the rotation axis imposed by the driving means and, as a result, the rotation of the disk generates forces which draw the disk away from the imposed rotation axis. The displacement of the mass center can be caused by labels on the disk, imperfect manufacturing of the disk, erroneous centering of the opening or other reasons. But it may also be related to the disk player and/or recorder itself.
A known solution to overcome the problems related to higher rotation speeds is to reduce the rotation speed until an acceptable level of noise, vibration and/or number of reading/writing errors is achieved. This of course reduces the data reading and/or writing rate.
It is an object of the present invention to find a device which allows to overcome the problems due to higher rotation speeds of the disk shaped data carrier.
The invention provides a device for rotating inside of a disk player and/or recorder a disk shaped data carrier having an opening around a center of the disk shaped carrier. The device comprises at least fixing means which allow to removably fix the disk by inserting a part of the fixing means in the opening and driving means which rotate the data carrier by acting on the fixing means. The driving means are at least partly mechanically connected to the disk player and/or recorder. The device further comprises side moving means which allow the fixing means to move inside the disk player and/or recorder in a rotation plane substantially perpendicular to an axis of rotation of the fixing means.
The fixing means move together with the disk inside the disk drive in a plane which has substantially a same orientation as centrifugal forces acting on a center of mass of a disk fixing means assembly which is located aside from a rotation axis of the fixing means imposed by the driving means. The vibrations on the disk player and/or recorder are reduced.
In a first preferred embodiment of the invention according to the invention the side moving means comprise sliding means which allow to move the driving means inside the player and/or recorder along directions which are parallel to the rotation plane and elastical elongation means fixed at one end to the player and/or recorder and at another end to the driving means, such that the driving means are positioned in a determined rest position at least when the driving means stop driving the data carrier.
An advantage of the preferred embodiment is that the fixing means may be mounted rigidly on e.g. a driving shaft of the driving means thus allowing for a very simple connection between driving means and fixing means.
In a second preferred embodiment according to the present invention the side moving means further comprise flexible transmission means through which the driving means act on the fixing means. An end of the flexible transmission means is connected to the driving means and another end is connected to the fixing means.
The second preferred embodiment allows to move the fixing means independently from the driving means. An advantage of this is that the moved mass is less than is if the driving means were to be moved as well.
In a third preferred embodiment according to the present invention the side moving means comprise first bearing means which are mounted on the fixing means, and the disk and/or recorder comprises at least a supporting surface parallel to the rotation plane, such that the first bearing means allow the fixing means to slide on the supporting surface while the fixing means rotate.
The third preferred embodiment shows a simple solution to realize a movement of the fixing means in the player and/or recorder.
In a fourth preferred embodiment according to the present invention the moving means comprise a sliding support and the disk and/or recorder comprises at least a supporting surface being parallel to the rotation plane; the sliding support slides on the supporting surface and the sliding support has a drive opening through which the driving means act on the fixing means.
The fourth preferred embodiment is particularly advantageous to reduce the intensity of friction between the moving means and the supporting surface since only the fixing means are driven and rotated by the driving means, i.e. the moving means do not have to rotate in the same way as the fixing means.
In a fifth preferred embodiment according to the present invention the side moving means comprise a sliding support having a drive opening through which said driving means act on said fixing means. The disk and/or recorder comprises at least a supporting surface which is parallel to the rotation plane, such that the sliding support slides on the supporting surface. In the device, at least an elongated part of the fixing means is fitted through the drive opening together with second bearing means which allow the elongated part to rotate inside the drive opening. The driving means comprise a rotor magnet mounted on the elongated part and a stator electro-magnet mounted on the player and/or recorder such that the rotor magnet and the stator electro-magnet cooperate as an electric motor. The device further comprises centering means which position the fixing means in a central position at least when the driving means stop driving the data carrier.
The fifth preferred embodiment allows to minimize a weight and size of the device according to the invention.
The invention further provides a device for rotating inside of a disk player and/or recorder a disk shaped data carrier having an opening around a center of the disk shaped carrier, the device comprising at least fixing means which allow to removably fix the disk by inserting a part of the fixing means in said opening, and driving means which rotate the data carrier by acting on the fixing means. The driving means are at least partly mechanically connected to the disk player and/or recorder. The fixing means comprise an elongated part; the driving means comprise a rotor magnet which is mounted on the elongated part and a stator electro-magnet mounted on said player and/or recorder such that the rotor magnet and the stator electro-magnet cooperate as an electric motor. The device further comprises centering means which position the fixing means in a central position at least when the driving means stop driving the data carrier.
The latter device for rotating inside of a disk player and/or recorder a disk shaped data carrier according to the invention is a mechanically simple and cheap way of realizing the invention.
The invention even further provides a device for rotating inside of a disk player and/or recorder a disk shaped data carrier having an opening around a center of said disk shaped carrier, which comprises at least fixing means allowing to removably fix the disk by inserting a part of the fixing means in the opening, and driving means for generating a driving force to rotate the data carrier. The driving means are at least partly mechanically connected to the disk player and/or recorder and comprise compressor means to generate a stream of air and canalization means to direct the stream of air onto a surface which belongs to the data carrier and/or the fixing means such that a driving force is transmitted to the data carrier which sets the data carrier into rotation and such that an air cushion lifts the data carrier and the fixing means reducing mechanical friction between the fixing means and the driving means. The device further comprises centering means which position the fixing means in a central position at least when the driving means stop driving the data carrier.
The latter device according to the invention is particularly advantageous because it reduces sources of frictions.